The invention relates to a method for preparing a high-conductivity porous copper foil based on a brass strip. The method comprises the following steps that firstly, the surface of the brass strip iscleaned, then the surface of the brass is treated by using an aqueous solution of sodium borohydride, high-temperature annealing treatment or normal-temperature electrochemical treatment is conductedon the brass at a certain temperature to completely or partially remove zinc in the brass, and finally the high-conductivity porous copper foil is obtained. Compared with an original brass strip, theconductivity of the porous copper foil is increased by 60% or above. The method can prepare the porous and high-conductivity copper foil, and can be applied to the direction of electrical equipment such as a battery current collector, a wire and cable shielding layer, a circuit board line and the like.